1. Field of the Invention
This invention relates to an improved condition responsive valve construction and to a method of making the same.
2. Prior Art Statement
It is well known to provide a condition responsive valve construction for varying the output pressure of the valve construction in relation to a movable part of a condition responsive means that is moved in relation to the condition sensed thereby, the valve construction having a housing means provided with an inlet to be interconnected to a fluid pressure source and an outlet separated from the inlet by a main valve unit and being adapted to be interconnected to vent by a vent valve unit, the valve units being controlled by the condition responsive means.
For example see the following three items:
(1) U.S. Pat. No. 3,305,172 to Duchek, et al.
(2) Thermal Air Valve No. B 54X25 manufactured by the Rockford Clutch Division of the Borg-Warner Corp. and illustrated and described in the U.S. Pat. No. 3,848,622 to Cummings, III.
(3) U.S. Patent to Ferris, No. 3,066,552.
The condition responsive valve construction of item (1) above appears to have the vent valve unit thereof varied by means of a fluid presssure change acting directly between a movable part of the vent valve unit and the movable part of the condition responsive means whereas the condition responsive valve construction of item (2) above appears to have the vent valve unit thereof varied by means of a rigid valve stem acting directly between and against a movable part of the vent valve unit and the movable part of the condition responsive means. The condition responsive valve construction of item (3) above appears to have a movable vent valve member of the vent valve means thereof varied relative to a fixed vent valve seat by means of a compression spring acting between the vent valve member and a movable part of the condition responsive means thereof.